base petrol should more or less the same but the additive formula is different.
yup, they are all about the same. used to work at Caltex and my colleagues told me these:
from Mr A (retail): of course on a personal basis, else he will loose his job... hahahaha
RON92 = RON92, RON95 = RON95, RON98 = RON98
differences are in the additives (e.g. cleaning agents to clear the injectors and piston head, aid combustion, etc) and color dyes (that's why some red, some green, some yellow in color) added to support marketing claims of "cleaner greener" gasoline.
we’re basically paying a lot more for a little bit differential gain
from Mr B (oil trading): much more technical
although RON levels may be the same, geographical source of the crude makes a difference. crude extracted from different regions have different compositions of hydrocarbon and thus affects the “quality” and pricing of gasoline derived.
the petroleum industry generally classifies crude oil by the geographic source (e.g. saudi, russia, malaysia, etc.), its API gravity (density), and by its sulfur content. crude is considered light if it has low density (heavy if high density) and categorized as sweet if it contains relatively little sulfur, or sour if it contains substantial amounts of sulfur.
light crude is more desirable as it produces a higher yield of gasoline, sweet crude requires less refining to reduce sulfur contents (there are controls to max sulfur levels allowable to meet environmental standards).
problem is, we won't get to know where the gasoline is from which crude source unless we are “insiders”
